Sewing-machine.



No. 679,9I4. Patented Aug. 6, 190|. H. P. RICHARDS. SEWING MACHINE.

(Application led Sept. 12, 189B.\ 4 (No Model.) 4 sheets-'sheer no.679,9l4.

Patented Aug. 6, |90I.

lH. P. nlcHAnns. SEWING MACHINE.

(Application lvd Sept. 12, 1898.)

(No Model.) Sheets-Sheet 2.

ma' fm Tu: aonms Urns ou., moro-uma.. wAsNxNnroN. u t:4

No. 679,9I4. Patented Aug. 6, |90I.

H. P. RICHARDS.

1 SEWING MACHINE.

(Application med sept. 12, 189s.)

4 Sheets-Sheet 3.

(No Model.)

fitness e @M s l Inventor No. 679,9l4. Patented Aug. 6, |901. H. P.RICHARDS.

SEWING MACHINE.

(Application Bled Sept. 12, 1898.)

4 Shee1s-`sheet 4. Y

(No Model.)

Invent-f Witnesses TH: ohms Pmns cu., PHnToLlrHa. wAsHmGToN. nv c.

i UNITED. STATES PATENT CEEICE. f

HUBERT P. RICHARDS, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TO J.

EVARTS TRACY, OF PLAINFIELD, NEW JERSEY.

SEWING-MACHINE.

SPECIFICATION forming part of Letters" 15a/cent No. 679,914, datedAugust 6, 1901. Application tied september 12,1a9e`. sentira. 690,730.(Nomnaem To @ZZ whom, it may concern:

Connecticut, have invented certain new and useful Improvements inSewing-Machines, of which the following is a specification.

This invention relates in a general way to sewing-machines of that classin which the stitch-making mechanism includes a reciprocatory needle, arot-ary looper adapted for carrying successive loops, and means forreciprocating the needle and rotating the looper and whereby the loop ofthe needle-thread may be formed and be engaged by and carried entirelyaround the looper to inclose a lower thread to form a lock-stitch or maybe carried through a preceding loop to forni a chain-stitch or a chainlock-stitch; and the invention more particularly relates to asocalledfcombined lock-stitch and chainstitch mechanism embodying instrumenta-lities normally operative for forming a lockstitch and alsoembodying a stitch-changing device shiftable into position to engagesuccessive loops and to so act thereon as to elect a change in the formof stitch made.

An object of the invention is to provide a differential stitch-makingmechanism including an adjustable tension device andautomatically-operable adjusting means for varyt ing the resistance oreffective tension ot' the tension device on the needle-thread inaccordance with the requirements as determined by the varying conditionspresent in the making of different stitches and at dierent points in theoperation of forming any particular stitch.

A further object of the invention is to provide in a stitch-makingmechanism embodying a rotary looper adapted for carrying two loopssimultaneously a stitch-changing device operative independent of thelooper for engaging one loop and for holding the same in such positionthat the next succeeding loop will during'the rotation of the looperpass therethrough, a tension device for controlling the tension oftheneedle-thread, and means operativo 4with the stitch-changing devicefor decreasing the stress of the tension device upon the needle-threadwhen the stitch-chan ging device is shifted into operative relation withthe looper and for increasing the stress Be it known that I, HUBERT?.RICHARDS,A4 a citizen of the United States, residing in New. Britain, inthe county of Hartfordand State of,

`when the stitch-changing device is thrown out of operative relationwith the looper, as re- :quired when the stitch-making mechanism isforming chain-stitches and lock-stitches, re-

spectively.

A further object of the invention is to provide in a stitch-makingmechanism embodying a rotary looper adapted for carrying a plurality ofloops simultaneously a stitchchanging device independent of the looper`for successively engaging succeeding loops and `for holding said loopsin such position that every succeeding loop will pass through apreceding loop, a tension device for controlling *the tension of theneedle-thread, and two independently-operating means, one o f which isautomatically operated by a cam on the looper-driver shaft and iseffective for positively varying the tension at predetermined points inthe rotation of the looper and the other of which is automaticallyoperative with the stitch-changing device and is effective for changingthe degree of tension on the needlethread, according as a chain-stitchor a lockstitch is being made.

In the drawings accompanying and forming part of this specification,Figure l is a vertical longitudinal section of a sewing-machineembodying my present improvements, parts being broken away. Fig. 2 is ahorizontal section taken on a line corresponding to the dot-ted line aa, Fig. l, showing the parts below said line. Fig. 3 is an end view ofthe machine as seen from the left in Fig. 1. Fig. 4 is a verticalcross-sectional view taken on a line corresponding to the line b b, Fig.l, looking toward the left in said gure. Fig. 5 is a cross-sectionalview similar to Fig. 4,

taken on a line corresponding to the dotted line c c, Fig. 1, lookingto'ward the left in said figure. Figs. G, 7, 8, and 9 are perspectiveviews of the looper, needle, a portion of the Work-plate, and a piece offabric, illustrating, respectively, four successivepositions of theparts during the formation ofalock-stitch and indicating the positionsof the loops when the fabric is swung about the needle to form a stitchat an angle to the preceding stitch. Fig. lO is an enlargedcross-sectional view of the tension device for the needle-thread andapor- IOC tion of its actuating instrumentalities,the said section beingtaken on a line corresponding to the dotted line b b, Fig. 1. Fig. 1lisa crosssectional view of the parts shown in Fig. 10, taken on a linecorresponding to the dotted line e e in said figure and showing theparts above said line. Fig. 12 is a side view of a portion of thefeed-adjusting device detached. Fig. 13 is a perspective view of thepivot-plug of said feed-adj usting device detached. Fig. 14 is adiagrammatic view illustrating the relative movements of the needle andlooper and their actuating devices.

Similar characters designate like parts in y all the figures of thedrawings.

In the drawings only so much of a sewingmachine is shown as is deemednecessary to illustrate the application and mode of operation of mypresent improvements. y

My improved sewing-machine will usually comprise a framework,(designated by A,) which may be of any suitable general coustruction,for carrying the working parts of the machine; avertically-reciprocatory needle-bar N, carrying the needle N; ahorizontal needle-bar-actuating shaft D, (shown asa crankshaft,)journaled in suitable bearings in the framework and operativelyconnected with the needle-bar by a crank and link in the usual manner; arotary looper S, disposed at an inclination to the path of movement ofand below the needle-bar and having 'a plurality of loop-takers orhooks; a'looper-guide G, supported by a bracket G' on the frame andextending partially around the looper; a looper-supporting driver H; ahorizontal looper-actuating shaft D', supported 'in suitable bearingsbelow the bed-plate of the machine; a main driving-shaft D2,horizontally disposed in parallelism with and at one side the axis ofthe looper-actuating shaft and having a crank operatively7 connectedwith the crank of the needle-bar shaft by a link or pitman D in theusual manner; a two-to'- three train of gears E between and operativelyconnevcting the main driving-shaft and looper-actuating shaft; feedmechanism operated from the main driving-shaft; a presserbar P, having apresser-foot 7 cooperating with the feed-plate of the feed mechanism forholding the fabric; a rock-shaft D3, journaled in the framework at oneside of the needlebar-actuating shaft D and operatively connected withthe presser-bar by a crank in a wellknown manner and having meanswhereby said shaft may be rocked to raise or lower the presser-bar; astitch-changing device (designated in a general way by W) shiftable intoand'out of operative relation with the looper and effective when'inoperative relation with the looper for engaging a loop and holding thesame in such position as to permit the next succeeding loop to passtherethrough; means operated by the main driving-shaft for actuating thestitch-changing device; a tension device (designated in a general way byT) for controlling the needlethread, and two independenttension-modifying devices, (designated by T and T2, respectively,) theformer of which is controlled by a cam on the inainrdriving-shaft and iseffective for varying the tension at predetermined points in therotation of said shaft and the latter of which is in operativeconnection with thestitch-changing device and is effective for operatingthe tension device to change the tension of the needle-thread when thestitchchanging device is shifted into or out of'operative relationwiththe looper.

The framework of the machine, which may be of substantially the samegeneral construction as the framework of the machine del scribed inLetters Patent of the United States No. 574,573, granted to Francis H.Richards January 5, 1897, to which reference may be had, usuallycomprises a horizontal bed-plate 2, having a dependinglooper-guide-supporting bracket G' at the work-supporting end thereof, ahollow upright 4 at the opposite end of the bed-plate, a horizont-al arm5 above said bed-plate, and arvertical needle-bar-receivin g head 6 atthe free end of the arm 5.

The nee'dle-bar N and presser-bar P are shown, as in the patent referredto, axially coincident, the needle-bar being supported for reciprocatorymovement in the presserbar, which is in turn supported for verticalmovement in the head 6, and is furnished at the lower end thereof withthe presser-foot 7, a resistance-spring (not shown) being in practiceprovided, as in said patent, for regulating the pressure of thepresser-foot upon the fabric.

The rotary looper S maybe similar in a general way to the discoidalloop-taker described in the patent referred to and is supported belowthe bed of the machine for rotative movernent in a plane oblique to thepath of the needle, (see Fig. 1,) said looper being guided in itsrotation and held against movement transversely of its path of rotationby the parti-circular looper-guide G, which extends around the lowerportion and has a raceway for receiving the perimeter of said looper,such raceway being in practice of sufficient depth to permit a slightdiametrical movementof said looper. Said looper will in practice befurnished with some suitable meanssuch, for instance, as that describedin the v patent referred to, but not shown in the accompanyingdrawings-for carrying a lower thread, cop, or bobbin and will also beprovided with some suitable tension device for the lower thread. In theform shown the looper is furnished with a set of threecorrespondingly-disposed loop-taking hooks, which are designated by 7L,h', and h2, respectively, and also has formed in the inner face thereofa series of driver-sockets 8, disposed preferably concentric to the axisof the looper and equidistant to one another, which sockets are adaptedfor receiving corresponding driving-pins 9 upon driving-arms 10 of thedriver H, which driver may be of the same general IOC- IIO

w www shaft-the looper having three equidistant` hooks-is connected tothe main driving-shaft by a two-to-three train of gearing E in such amanner as to have two complete rotations to every threecompleterotations of the main drivingshaft, and consequently hastwothirds of a complete rotation at every complete reciprocation of theneedle-bar, the ratio of movement between the looper and needle beingthe saine in the present instance as in the patent referred to. Thetwo-to-three train of gears E is shown comprising an internal gear-wheel12, ixedto the end of the shaft D', and a pinion 13, fixed to the end ofthe driving-shaft D2 and meshing with said internal gear.

The feed mechanism shown comprises two substantially parallelrock-shafts R and R', located at opposite sides, respectively, of thelooper-actuating shaft D' and journaled in bearings below the bed-plate2 of the machine; two cranks 14 and 15, fixed to the outerends of therock-shafts R and R', respectively; a feed member K pivotally secured atone end to the outer end of the crank 14 and having the opposite endthereof bifurcated and in shiftable connection with a stud 15', fixed tothe outer end of the crank 15; two cranks 16 and 16', secured to theinner ends of the rockshafts R and R, respectively; a compoundfeed-member-advancing linkage operatively connecting the crank 16 andeccentric 18, and

' a feed-member-elevating linkage operatively connecting the crank 16'and said eccentric, said feed member advancing linkage andfeed-member-elevating linkage being so constructed Yand disposed and sotimed in their movements oneV relatively to thc other that during onecomplete cycle of movements of the driving-shaft D2 and eccentric 18from a normal ineffective position the elevatinglinkage will be firstshifted to impart a feedmember-elevating movement `to the rockshaft R'and its crank, after which the feedmember-advancinglinkage will impart afeedmember-advancing movement to the rockshaft R and its crank and afterwhich the elevating-linkage will operate to depress the feed member, andthe feed-member-advancing linkage will then operate to impart aretractive movement to said feed member or feed-plate, the operations ofthe two linkages taking place in alternation. The feed-member-advancinglinkage in the form thereof shown in the accompanying drawings comprisesa short vertically-disposed link 19, pivoted at its lower end to aprojection on the strap 2O of the eccentric 18, and a horizon-'tally-disposed link 2l', pivoted at its inner end to the upper end ofthe link 19 and pivotally connected at its outer end to the free end of`the crank 16. The feed-member-elevating linkage is shown comprising acrank-shaft R3, disposed intermediate the rock-shaft R' and maindriving-shaft D2 and having two differently-disposed cranks 24 and24',respcctively,

a horizontallydisposed link 25, preferably formed integral with andconstituting a part of the eccentric-strap 2O and pivotally connected atits outer end to one of the cranks, as 24, of the crank-shaft R3, and averticallydisposed link 26, pivotally connected at its lower end to thecrank 2li' of said crank-shaft R3 and pivotally connected at its upperend to the crank 16 of the rock-shaft R. Thel dispositions of the cranksand eccentrics of the feed-member-elevating linkage will be such as tosecure a comparatively short stroke of the feed-member-elevating crank15 at each semirotation of the drivingshaft D2.

As a means for changing the working stroke of the feed-plate K andsimultaneously chan ging the working position of said feed-plate I haveprovided a feed-adjusting device, (designated in a general way by M,)which in the preferred form thereof comprises a slidebar 27, supportedfor horizontal movement in a way 27', formedin a portion of theframework below the bed-plate of the machine,

and which slide-bar has at the inner end thereof a depending portion 28,which is piv- Votally and adjustably connected to the link 2lintermediate the ends thereof and constitutes the fulcrum on which saidlink swings and also governs the range of movement of said link.

For the purpose of forming a sliding pivotal connection between theadjusting device M and link 2l the depending portion 28 of said devicehas a transverse socket- 29 formed in one face thereof, in which isseated a bifurcated plug or pivot 30, the bifurcated end of which plugstraddles the link 21, said plug being supported for oscillatorymovement in the depending portion 28 of said device M, as will beunderstood readily by reference to Figs. l2 and 13 of the drawings.

As a convenient means for shifting the adjusting device'M to change thefulcrum of the link 2l, and consequently the working stroke of thefeed-plate K, I have provided a shifting device, which may be a screwextending through a guideway in the bed-plate of the machine (see Fig.5) and into the slidebar 27 of the adjusting device M and having at itsupper end a knurled head, whereby the same may be turned to hold theadjusting device in its adj usted position.

Inasmuch as the general operation of the looper and Afeed mechanisms inthe present machine in forming a lock-stitch is somewhat similar to thatof the same parts in themachine described in the patent referred to, adetailed description of this operation 'is deemed unnecessary, it beingsuflicient to IOO IIO

tation thereof to inclose the lower thread and form a lock-stitch, eachpreceding loop being drawn up by a succeeding loop as said succeedingloop is partially drawn out by the looper during the rotation thereof,as will be understood by reference to Figs. 6 to 9, inclusive, of thedrawings. In the organization of mechanism shownin the accompanyingdrawings the looper S will be constantly rotated in one direction duringthe operation of sewing, preferably in the direction of the arrows inFigs. 3, 4, 5,and 6 to 9 of the drawings, and toward the front side ofthe machine.

As a convenient and simple means for changing the form of stitchresulting from the normal operation of the needle and looper mechanismshereinbefore described without effecting a change in the direction ofmovement of the looper or feed device or in the .mode of operation ofthe several lock-stitch mechanismsto wit, the looper mechanism, theneedle mechanism, and the feed mechanism-I have provided astitch-changing device (designated in a general way by W) which is inall essential characteristics substantially the same as thestitch-changing device described in my Patent No. 607,079, dated Julyl2, 1898, said stitch-changing device being shiftable into position forcoperating with the looper and being effective for engaging the upperportions of successive loops and for deflecting said portions laterallyof the path of the needle, so that succeeding loops may pass through`preceding loops and cause the stitch-forming mechanism to produce achain-stitch or a chain lockstitch. The construction andorganzation ofthe stitch-changing device are such that the same may be thrown into orout of oper- `ative relation with the looper to change the form ofstitch made by the stitch mechanism without the necessity of changingthe direction of rotation of the looper or the direction of movement oftheV feed mechanism and without the removal or substitution of parts, asheretofore necessary in machines of ordinary construction, and hencesaid device forms with the looper mechanism a changestitch mechanismadapted for making different kinds of stitches as desired.

The stitch-changing device W, as shown most clearly in Figs. 2 and 4t ofthe drawings, comprises a loop-diverter 60, (shown as a lever,)fulcrumed at 60 below the bed-plate of the machine for horizontaloscillation across the path of the loops, actuating means for theloop-diverter, which is herein shown as a lever 62, fulcrumed at 62' atone side the axis of the main driving-shaft D2, an actuatingrod 63,pivotally connected at one end to the actuating-lever 62 and at itsopposite end to one end of the loop-d iverterpO, and a cam 64, xed tothe driving-shaft D2, which has two oppositely-disposed working facesagainst which a roll 64 on the inner end of the actuating-lever 62bears, said cam being adapted for advancing and retract-ing theloop-diverter 60 across the path of the loops, as will be understood byreference to Fig. 2 of the drawings.

As a means for throwing the stitch-changing device out of and intooperative relation with the looper I have provided a throw-out deviceW', which is shown asa stud 62", supported for rotative and longitudinalmovement in a vertical bearing formed in the framework, which stud hasits lower end eX- teuding through the actuating-lever 62 and constitutesthe supportvand fulcrum for said lever, and I have provided inconnection with said stud a horizontally-disposed actuator 65, (shown asa headed pin,) extending through an inclined or cam groove 66, formed inthe upright 4, and having a head at the outer end thereof whereby thestud 62" may be rotated and simultaneously lowered to throw the outerend of the actuating-lever into operative engagement with the workingsurfaces of the actuating-cam 64E. This stud is provided with adepending lever-actuating projection 67, so disposed Y (see Figs. 2 and4) that when the stud 62l is raised and rotated Vit will strike thelever at a point intermediate its fulcrum and the `outer end andthrowthe same toward the left, as seen in Fig. 2, thereby shifting theworking end of the loop-diverter from its working position out ofoperaative relation with the looper, the cam-groove 66 being upwardlyinclined, as shown most clearly in Fig. 3so that when the actuator 65IOO is shifted toward the left the stud 62, which carries theactuating-lever, will be raised and simultaneously rotated.

It will be obvious that other instrumentalities than those illustratedin the drawings may be employed for actuating the loop-diverter.Therefore it will be understood that I do not limit this invention tothe particular means shown.

The actuating-cam 64 is shown constructed to impart both advancing andretracting movements to the loop-diverter; but it will be obvious thatit might be constructed to impart a movement to said loop-diverter onlyin one direction and other means-be employed for imparting a movementthereto in the other direction.

In a sewing-machine of this class it is extremely desirable that meansbe provided for varying the tension of the needle-thread at dierentpoints in the rotation of the looper, the preferred construction beingone in which the tension of the thread may be decreased just before theengagement of a loop by a loop-taker, so as to prevent breaking of thethread during the rst stagegof the drawing out of the loop, the tensionbeing afterward increased just before the final drawing up of IIO in, LAAni U the preceding loop.V It is also important in sewing-machineshaving change-stitch mechanism for making different stitches that thetension should be changed in accordance with the requirements asdetermined by the kind of stitch being made, it being necessary, forexample, to put a greater tension upon a thread for the formation of alock-stitch than for the making of a-chain-stitch. In the present caseone of the main features of the invention is the provision oftension-modif yin g means automatically operative for increasing ordecreasing the tension on the thread during the making of each separatestitch, and I also employ meansfor changing the tension by a definiteamount when the mechanism is set for the making of another kind ofstitch from that for which it may have been set previously. Hereinafterthe tension-modifying means automatically operative during the making ofany stitch will be termed a tension-varying device and will control thetension device coperating directly with the thread, while thetension-modifying means, which determines the extreme degrees oftensionfor different stitches, will be termed a tension-changing device and inthe preferred form of the invention will be controlled directly by thethrowing of the stitch-changing device into and out of operation, it.being obvious,of course, that when the stitch-changing deviceisinoperative and the mechanism operates to make a lock-stitch the tensionshould be quite high, while when the stitchchanging device is throwninto position to cooperate with the looper and deflect the loops carriedtherearound the tension should be modified materially, so that it willbe much less than is necessary for the making of a lock-stitch.

For the sake of simplicity of construction a single thread-tensioningdevice-such, for example, as that indicated herein by T-will be usedordinarily, and this may be controlled by both the` tension-varyingdevice and the tension-changing device conjointly, these twotension-modifying devices being designated, respectively, by T and T2,as before stated.

The tension device shown in the drawings embodies two tension-plates,such as 35 and 36, one of which, as 35, may be supported on a suitableprojecting portion or boss 37 of the framework, the other being looselycarried in this instance by a sleeve 38, supported for reciprocation inalongitudinal bore in the boss 37, an adjustable stop or stop-nut, suchas 39, being secured to the upper screw-threaded end of the sleeve 3S,between which stop and the tension-plate '36 a coiled spring 40,encircling said sleeve, may work. In the construction shown the partwhich operates directly to vary the tension of this spring during eachstitch-making operation is a rod 41, supported for reciprocation in thesleeve 38 and having a notched opening or recess at one side thereof,one Wall of which forms an actuating member adapted to engage a pin,

such as 42, carried by the tension-plate 346 and extending througha slotiu the sleeve 38. It will be apparent that when the rod 41 is lifted thepin ,42, and thereby the upper tensionplate 36, will also beraisedslightly to decrease the tension on the thread between they plates. Inthe construction illustrated an actuating-rod 43 coperates at its upperend with the lower end of the rod 41 to lift the latter, a coiledretracting-spring being disposed. between the lower headed end 41 of therod 41 and some portion of the framework. At the lower end thereof therod 43 may carry a roll 44, which may rest upon a circumferentialcam-face 45 at one side of the cam 64 for the stitch-changing device,the spring at the upper end of the rod 43 serving to maintain the rolliu contact with such camface 4 5.

The tension-changing device which I prefer to use embodies a shortlever, such as 4G, Fig. l0, having a ball-bearing support 47 between itsends, this lever being mounted in a suitable opening in the framework.At its inner end the lever 46 engages the sleeve3S near the lower end ofthe latter, and at its outer end said lever is in position to beoperated by a thrust-rod to lower the sleeve and the stop-nut 39 toincrease the tension when the mechanism is set for the making of alockstitch, this tension being decreased, ofcourse, as soon as the rod49 is lowered. At its lower end said rod 49 is connected with the studor knob which controls the position of the stitchchanging device W andis operated thereby.

From theabove description it will be seen that the tension on theneedle-thread will be varied automatically by the operation of the rod43 during the making of each stitch, whatever Athe character of thelatter, and that the tension will be increased or decreased by a certaindefinite amount by the action of the rod 49, according as the mechanismis set for the making of a lock-stitch or a chain-stitch.

No claim is herein made to the feed mechanism shown and described, forit constitutes the subject-matter of my concurrently-pending applicationfiled April 12, 1900, Serial No. 12,516.

Having described my invention, I claim- 1. In a sewing-machine, thecombination, with stitch-forming mechanism, of a threadtensioningdevice, a stitch-changing device, and automatically-operativetension-varying means controlling said thread-tensioning device andcoperating with the stitch-changing device.

2. In a sewing-machine, the combination, with stitch-formingmechanism-of a threadtensioning device; a stitch-changing device; andmeans controlled by the stitch-changing device for actuating thethread-tensioning device to decrease the tension upon the thread whenthe stitch-changing device is thrown into operative position and toincrease said tension when the stitch-changing device is thrown to itsinoperative position.

3. In a sewing-machine, the combination, with stitch-forming mechanismembodying a rotary looper, of a thread-tensioning device; astitch-changing device Working on the loops of the thread; and atension-changing device operatively connected with said stitch-changingdevice.

4. .In a sewing-machine, the combination, with stitch-forming mechanismincluding a rotary looper, of a thread-tensioning device;automatically-operative tensionmodifying means controlling saidthreadtensioningde vice and operative for actuating the latter duringeach rotation ot the looper to vary the tension on the thread; astitch-changing device; and a tension -changing device controlled bysaid stitch-changing device.

5. In a sewing-machine, the combination, with stitch-forming mechanismnormally operative for making a stitch of one kind, ot' feed mechanism;a stitch-changing device independent of said feed mechanism andcontrolling the making of a stitch of another kind; a thread-tensioningdevice; and atension-changing device controlling said threadtensioningdevice and controlled by said stitch-changing device.

6. In a sewing-machine, the combination, with stitch-forming mechanismnormally operative for making a stitch of one kind, of feed mechanism; astitch-changing device independent of said feed mechanism andcontrolling the making of a stitch of another kind and shiftable intoand out of operation; a thread-tensioning device; and a tension-'changing device controlling said thread-tensioning device andcontrolled by said stitchchanging device.

7. In'a sewing-machine, the combination, with stitch-forming mechanismnormally operative for making a stitch of one kind and embodying arotary looper, of feed mechanism; a stitch-changing device independentof said feed mechanism and controlling the making of a stitch of anotherkind and shiitable into and out of operative relation Withthe looper; athread tensioning device; and a tension changing device controlling saidthread-tensioning device and controlled by said stitch-changing device.

S. I-n a sewing-machine, the combination, with lock-stitch-formingmechanism, of a chain-stitch-forming device shiftable into and out ofoperation; a thread-tensioning device; and a tension-changing devicecontrolling said thread-tensioning device and controlled by saidchain-stitch-forming device.

9. In a sewing-machine, the combination, With stitch-forming mechanismnormally operative for making a stitch of one kind. and embodying arotary looper having a plurality of loop-taking hooks, of astitch-changing device controlling the making of a stitch of anotherkind and automatically shiftable into engagement with successive loops aplurality of times during each rotation of the looper; athread-tensioning device; and a tensiona tension-changing device; aseparately-operative tension -varying device controlling thethread-tensioning device conjointly with said tension-changing device;and means for automatically operating said tension-varying device duringthe making of each stitch.

12. In a sewing-machine, the combination, With stitch-forming mechanismnormally operative for making a stitch of one kind, of a stitch-changingdevice controlling the making of a stitch of another kind; athread-tensioning device; a tension-changing device controlling saidthread-tensioning device and controlled by said stitch-changing device;a separately-operative tension-varying device controlling thethread-tensioning device conjointly with said tension-changing device;and means for automatically operating said tension-varying device duringthe making of each stitch.

13.- In a sewing-machine, the combination, lwith stitch-formingmechanism embodying reciprocatory needle mechanism and a rotary looper,of a tension device for the needlethread; a shiftable stitch-changingdevice; and tension-changing means controlling said tension device andthrown into action when the stitch-changing device is shifted.

14. In a sewing-machine, the combination, with stitch-forming mechanismembodying reciprocatory needle actuating mechanism and rotarylooper-actuating mechanism, of a tension device for the needle-thread, astitchchanging device; and automatically-operative tension modifyingmeans controlling said tension device, controlled by a part of thelooper-actuating mechanism and coperating With the stitch-changingdevice.

15. In a sewing-machine, the combination, with stitch-forming mechanismembodying needle-actuatingmechanism and looper-actuating mechanism andnormally operative for making a stitch of one kind, of a stitch-changing device controlling the'making of a stitch of another kind; atension device for the needle-thread; a tension-changing devicecontrolling said tension device and controlled by said stitch-changingdevice; and a separatelyoperative tension-varying device controllingsaid tension device conjointly with said tension-changing device andoperative by a part of the looper-actuating mechanism during the makingof each stitch.

IOO

IIO

16. In a sewing-machine, the combination, with stitch-forming mechanismembodying a needle and a looper and normally operative for making astitch of one kind, of a stitchchanging device controlling the making ofa stitch of another kind and operative for deiiecting each loop andholding it in such deflected position until a succeeding loop has passedtherethrough; a thread-tensioning device; and a tension-changing devicecontrolling said thread-tensioning device and controlled by saidstitch-changing device.

17. In a sewing-machine, the combination, with stitch-forming mechanism,of a tension device embodying a pair of tension-plates and a spring; atension-changing device controlling said spring; a separately-operativetension-varying device controlling said spring conjointly with saidtension-changing device; and means for operating said tension-vanyingdevice automatically during the making of each stitch.

18. In a sewing-machine, the combination, with needle mechanism and alooper, of

change-stitch mechanism, feed mechanism; a tension device embodying apair of tensionplatesand a spring, and a tension-changing deviceindependent of said feed mechanism `controlling said tension device andcontrolled HUBERT I). RICHARDS.

NVitnesses:

S. W. PoT'rs, HENRY BIssELL.

